The present invention relates to a brake system with slip control and, more particularly, to such a system comprising a pedal-actuated booster with a master cylinder to which the wheel brakes are connected via pressure-fluid lines. Such a system also includes an auxiliary-pressure source with a hydraulic pump and also with a pressure-compensating and pressure-fluid supply reservoir. It further includes wheel sensors and electronic circuits for determining the wheel rotational behavior and for generating electric braking-pressure control signals which serve to control electromagnetically controllable pressure-fluid inlet valves and outlet valves inserted into the pressure fluid lines for the purpose of slip control. It still further includes a regulating and pressure-monitoring valve which communicates with the auxiliary-pressure source, which is connected to at least one pressure chamber of the master cylinder and whose valve chamber communicates with the pressure-fluid supply reservoir and with the supply line leading to the inlet valves.
In a dual-circuit brake system of the type disclosed in W. German application No. P 35 02 451.8, filed Jan. 25, 1985, (corresponding to U.S. application Ser. No. 822,750, filed Jan. 27, 1986 by J. Belart et al now U.S. Pat. No. 4,685,747), there is provided a regulating valve which controls the pressure in the pressure fluid conduit leading from the pump to the two brake lines in dependence on the pressure in a working chamber of the master cylinder, with non-return valves being inserted into the pressure fluid conduit between the brake lines and the pump. Besides, this brake system provides a differential-pressure switch in the electronic circuit to recognize the presence of a differential pressure and to evaluate same. This differential-pressure switch is via special pressure lines communicating both with the pressure fluid conduit which leads from the pump to the brake lines and with a working chamber of the master cylinder.